Current systems and methods for determining defect sizes on a film layer on a wafer may include the use of high precision tools to deposit a number of polystyrene latex spheres of various known sizes onto the film layer, and then measuring their light scattering intensity response in normalized parts per million (nppm). These systems and methods may not account for varying film thickness over the surface of the wafer, or variations in film thickness from one wafer to another. In addition, it is time consuming to deposit these polystyrene latex spheres.
The existing methods for measuring the thickness of a film on a wafer may present a variety of drawbacks. For example, existing methods may only provide measurements for a few points on the wafer rather than across the entire surface of the wafer. In addition, existing methods may be time consuming, as each sample may require significant time to complete. As a result, it may be difficult to determine the thickness of the film across the entire wafer surface in an accurate and timely manner.
Therefore, there exists a need for a method and apparatus to determine the sizing of defects by measuring the film thickness of a wafer, without the aforementioned shortcomings.